homesick angel
n. Pilot‘s term for an airplane that climbs faster than expected.

Example Citations:
On the transcript, a comment from TWA Captain Steven Snyder six minutes before the explosion appeared intriguing and a little eerie. “Seems like a homesick angel here,“ Capt. Snyder said, using pilot lingo to say the plane was climbing faster than normal.
—Pat Milton, “Flight 800 climbed like a ‘homesick angel‘,“ The Associated Press, December 8, 1997

Tim said getting the plane up was a great accomplishment and that Brad had been babying the balky airplane for days. It‘s now flying like a homesick angel, to quote that marvelous line known to all flyers.
—Zan Thompson, Los Coyotes: Beauty to howl about,“ Los Angeles Times, October 22, 1989

Earliest Citation:
Others flew with full down trim on the transmitter, and about half forward stick, but was at a disadvantage for the turn sometimes required not “up“ but “down“ and when pressure was relaxed on the forward stick, the glider would climb like a “homesick angel“, thus killing the forward speed.
—“Let‘s go to the (glider) races,“ Zephyr, May 1, 1970